As a gas turbine engine operates, airborne contaminants may accumulate on various components of the engine, such as the blades and the vanes of the compressor. Although the gas turbine engine may include an inlet air filtration system, a certain degree of contaminant accumulation may be unavoidable and may depend on various environmental conditions at the site of operation. Over time, accumulation of contaminants on the compressor blades and vanes may restrict airflow through the compressor and may shift the airfoil pattern. In this manner, such accumulation may adversely impact the overall performance and efficiency of the gas turbine engine, particularly resulting in decreased power output, increased fuel consumption, and increased operating costs.
In order to reduce contaminant accumulation, the gas turbine engine system may include a water wash system for removing contaminant particles from the compressor blades and vanes. For example, an on-line water wash system may be used to remove contaminant particles from compressor blades and vanes via a flow of water while the gas turbine engine is operating at full speed and is loaded. The on-line water wash system may deliver the flow of water upstream of the compressor via an on-line manifold including nozzles positioned at the gas turbine inlet plenum. The nozzles may create a spray mist of water droplets in this region of relatively low velocity air, and the negative pressure produced by the operating compressor may draw the spray mist into contact with the compressor blades and vanes for contaminant removal.
An off-line water wash system may be used in a similar manner to more effectively remove contaminant particles via a flow of water and detergent while the gas turbine engine is shut down or operating at a turning gear speed and is not loaded. The off-line water wash system may deliver the flow of water and detergent upstream of the compressor via an off-line manifold including nozzles positioned at the gas turbine inlet plenum or other locations along the gas turbine engine. In certain applications, a water wash system may be configured to operate in either an on-line mode or an off-line mode. In this manner, on-line washes may be carried out periodically to increase performance and efficiency of the gas turbine engine when the operating schedule does not permit shutdown time so as to perform a more effective off-line wash. The frequency and duration of on-line and off-line washes may vary depending on the degree of contaminant accumulation and environmental conditions at the site of operation.
Generally described, a water wash system may include a water tank, a detergent tank, a pump, and a mixing mechanism configured to supply a flow of water and detergent for an off-line wash. The water tank, the detergent tank, the pump, the mixing mechanism, and other components may be positioned on a water wash skid or otherwise. The water wash system also may include various manifolds, feed lines, discharge lines, and valves for directing a feed flow of water and detergent into the gas turbine engine and allowing a discharge flow of water, detergent, and contaminant particles to drain therefrom.
Performing an off-line wash with certain water wash systems may be a very complex and time-consuming process that requires several hours of shutdown time and multiple operators to complete, which results in a substantial cost to the operation site. Specifically, the off-line wash process may require manually opening and closing numerous valves at certain times and in a particular sequence to properly control the flow of water and detergent into the gas turbine engine and to allow the discharge flow of water, detergent, and contaminant particles to drain therefrom. Manual errors in controlling these flows may result in a low-quality wash and may unnecessarily extend the duration of the wash. Moreover, the off-line wash process may require physically monitoring certain parameters of the water wash system and making certain adjustments to ensure acceptable quality of the wash. Again, manual errors or improper subjective determinations in monitoring these parameters and making adjustments may result in a low-quality wash and may unnecessarily extend the duration of the wash. Overall, performing the off-line wash process with certain water wash systems may produce varying results with respect to the degree of contaminant removal achieved and the shutdown time required, which ultimately may adversely impact the performance and efficiency of the gas turbine engine and total operating costs.
There is thus a desire for an improved water wash system for removing contaminant particles from a gas turbine engine to improve overall performance and efficiency of the gas turbine engine. Specifically, such a water wash system should simplify performance of an off-line wash process and reduce the amount of shutdown time and the number of operators required to complete an off-line wash. Further, such a water wash system should reduce the incidence of errors in controlling the various flows and monitoring and adjusting the various operating parameters of the water wash system.